About two-thirds of the way down this page of Great War recordings is a track listing called "Gas Shells Bombardment - British Troops Advancing on Lille." It is very eerie; you can hear the battery commander giving orders, and the guns fire, followed by the whistle of the shell (or more accurately, the nose-fuse) as it travels towards the enemy.

The sound of Gulf War pt 1 for me was morse code. 12 hours a day of morse code for months on end. Looking back 20+ years ago, I can't believe I actually did that. If you said my job was friggin morse code today I'd say, "Hells no!". Guess that's why the military gets them young. :-S